Running out of stock is an expensive prospect for any retailer. Barring a suitable replacement, the retailer misses out on revenue. Even if there is a replacement, the customer might be frustrated, which could mean less customer loyalty and lower lifetime value. The pandemic made this even tougher for retailers, thanks to the combination of supply-chain disruptions, increased spending on consumer goods, and labor force shortages. Recent research shows that by May 2020, the frequency of stockouts within the United States had increased to more than 35% — more than double the pre-pandemic level of 14%.